World Health Organization
منظمة الصحة العالمية
Organisation mondiale de la Santé

Interpretation of symptoms as a cause of delays in patients with acute myocardial infarction, Istanbul, Turkey


PDF version

Sema Koc,1 Zehra Durna2 and Semiha Akin2

تفسير الأعراض باعتبارها سبباً لتأخر تعافي مرضى احتشاء عضلة القلب الحاد، إسطنبول، تركيا

سيما قوج، زهرا درنا، سميحة آقين

الخلاصة: هدفت هذه الدراسة المقطعية الشاملة إلى تقييم تفسير الأعراض باعتبارها سببا لتأخر تعافي مرضى احتشاء عضلة القلب الحاد. أُجريت الدراسة في إحدى المستشفيات الجامعية في إسطنبول، تركيا. وشملت العينة 93 مريضاً: 73 منهم من الذكور، بمتوسط أعمار 57.89 (12.13) عاما وتراوح زمن التأخر قبل الوصول إلى المستشفى ما بين 15 دقيقة إلى 10 أيام، وبلغ الزمن الوسيط ساعتين (مدى بين الربعين: 9.50). انتظر المرضى زوال الألم (%48.4) وحاولوا تهدئة أنفسهم (%39.8). وعزا معظم المرضى الأعراض المتصلة باحتشاء عضلة القلب إلى أسباب غير أمراض القلب. ولدى إجراء تحليل انحدار لوجستي متعدد المتغيرات، صنِّف نوع احتشاء عضلة القلب استناداً إلى نتائج تخطيط كهربية القلب (OR= 5.18; 95/CI= 1.69-15.91; p= 0.004) وارتبط كمتغير مستقل بزمن التأخر الطويل قبل الوصول إلى المستشفى، مما يدل على أن المرضى الذين يعانون من ارتفاع في الوصلة ST يسعون إلى الحصول على رعاية صحية مبكرة. ويسبب التفسير الخاطئ للأعراض والمفاهيم الخاطئة بشأن العلاج الطارئ عند حدوث احتشاء عضلة القلب إلى تأخر قبول المرضى مما قد يؤثر على علاجهم.

ABSTRACT This cross-sectional study aimed to assess interpretation of symptoms as a cause of delays in patients with acute myocardial infarction (AMI). It was conducted at a university hospital in Istanbul, Turkey. The sample included 93 patients: 73 male, mean age 57.89 (12.13) years. Prehospital delay time ranged from 15 minutes to 10 days, with a median of 2 hours (interquartile range: 9.50). Patients waited for pain to go away (48.4%) and tried to calm down (39.8%). Most patients attributed AMI-related symptoms to a reason other than heart disease. In a multivariate logistic regression analysis, the type of AMI was classified based on electrocardiography findings (odds ratio 5.18, 95% confidence interval: 1.69–15.91, P=0.004) and was independently associated with a long prehospital delay time, indicating that patients with ST segment elevation MI would seek early medical care. Misinterpretation of symptoms and misconceptions about emergency treatment during AMI cause delays in admission and may affect treatment.

L’interprétation des symptômes comme cause de délais pour les patients victimes d’un infarctus du myocarde aigu, Istanbul (Turquie)

RÉSUMÉ La présente étude transversale visait à évaluer l’interprétation des symptômes comme cause de délais pour les patients victimes d’un infarctus du myocarde aigu. Elle a été conduite dans un centre hospitalier universitaire à Istanbul, en Turquie. L’échantillon incluait 93 patients, dont 73 hommes, d’un âge moyen de 57,89 ans (12,13). Le temps d’attente avant de se rendre à l'hôpital était compris entre 15 minutes et 10 jours, avec une médiane de 2 heures (écart interquartile : 9,50). Les patients attendaient que la douleur disparaisse (48,4 %) et essayaient de se calmer (39,8 %). La majorité des patients attribuaient les symptômes de l’infarctus du myocarde aigu à une autre raison qu’une maladie cardiaque. À l’analyse de régression logistique multivariée, le type d’infarctus du myocarde aigu était classifié selon les résultats de l’électrocardiographie (odds ratio de 5,18, intervalle de confiance à 95 % = 1,69-15,91, p=0,004) et avaient une association indépendante avec un temps d’attente préhospitalier long, ce qui indique que les patients subissant un infarctus du myocarde aigu avec élévation du segment ST recouraient rapidement à des soins médicaux. Une mauvaise interprétation des symptômes et des idées reçues sur les traitements d’urgence prodigués lors d’un infarctus du myocarde aigu étaient à l’origine de délais d’admission et peuvent affecter le traitement.

1Sisli Vocational School Emergency and First Aid Program; 2Florence Nightingale Hospital School of Nursing, Istanbul Bilim University, Istanbul, Turkey (Correspondence to: Semiha Akin: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , This e-mail address is being protected from spambots. You need JavaScript enabled to view it )

Received: 18/11/15; accepted: 30/10/16


Mortality associated with acute myocardial infarction (AMI) occurs within the first 2 hours after the onset of symptoms, and common complications include recurrent ischaemia, reinfarction, ventricular arrhythmia and cardiac death (1–3). The time between onset of MI symptoms and initiation of coronary reperfusion is a determining factor of morbidity and mortality (2, 4,5). Early recognition of AMI-related symptoms and strategies for enhancing early diagnosis and treatment avoid fatalities and maintain quality of life by improving coronary reperfusion and reducing the possibility of death from ventricular arrhythmia (2,6,7). Mortality rate from AMI is reported to be high before arriving in hospital (1,8). Many patients with symptoms of AMI wait for a long time before seeking treatment (9). It has been reported that the median delay in patients with AMI ranges between 1.5 and 6.5 hours (10).

Public awareness of symptoms of MI and the importance of seeking immediate treatment is vital for avoiding delays in patients with AMI and preventing associated complications. There are many factors associated with delays in seeking early medical help in patients with AMI. Many patients with MI do not associate chest pain with heart problems, and therefore, admission for treatment is delayed because of the denial of complaints (10–12). Dracup & Moser found that patients did not appraise the symptoms as serious or as originating from the heart and waited to see whether symptoms disappeared (10).

Studies conducted in Eastern Mediterranean countries found long delays among Jordanian (13,14), Egyptian (15), Greek (16) and Israeli (17) patients with AMI. Other studies in Eastern Mediterranean and Asian countries also found that the sociodemographic (6,14,15,18) and clinical (6,16,19) characteristics, interpretation of symptom nature (14,15,19,20) and transportation of patients with AMI (6,20) predicted early access to medical treatment. Cognitive status and emotional variables (14,15,21) influenced the symptom interpretation and care-seeking behaviour.

Education for early recognition of symptoms associated with AMI could help with shortening the decision time for patients and promoting active behaviour in decreasing delays in patients with AMI (6,20). Investigating the factors associated with delay in AMI patients could increase the rate of early admission and administration of interventional treatment. This study aimed to assess interpretation of symptoms as a cause of delays in patients with AMI. We asked the following questions. (1) Do patients with AMI symptoms delay seeking treatment? (2) What are the prehospital interpretations of symptoms, and the predictors that may contribute to delay in patients with AMI?


Study sample, setting and procedure

We conducted a cross-sectional study in the Cardiology Department of a university hospital in Istanbul, Turkey. Around 600 patients were treated for AMI at the hospital in 2012.

The study sample was selected using purposive sampling, which is a nonprobability sampling method. We did not use any formula for sample size calculation. All patients who were admitted to the Cardiology Department between 1 June and 31 July 2013 were invited to participate. The inclusion criteria was as follows: (1) diagnosis of AMI; (2) consent to participate in the study; (3) age ≥18 years; (4) stable haemodynamic status (normal blood pressure measurements and pulse rates, sinus rhythm, absence of arrhythmias) following emergency management (percutaneous coronary intervention) of AMI; and (5) ability to communicate verbally, and read, understand and speak Turkish.

One hundred and twenty-six patients were approached in the 2 months. Fourteen patients were excluded because they did not have a stable haemodynamic condition or underwent some additional therapeutic interventions for AMI (e.g., elective angiography); 12 patients were not willing to participate in the study; 2 patients were unable to communicate due to symptoms or memory loss; and 5 patients felt too tired to participate. In total, 93 AMI patients participated in the study.

Ethical considerations

The research conformed to scientific and ethical principles outlined in the Declaration of Helsinki. Approval was obtained from the Ethics Committee of the hospital prior to the study. The study was approved by the Hospital Review Board. Patients were informed about the purpose of the study and guaranteed confidentiality. All patients enrolled in the study gave written informed consent to participate in the study.

Data collection

After obtaining signed informed consent, all participant information was collected from the patients themselves and medical records. Face-to-face interviews were carried out in a private/separate area for an average of 20 minutes. Data about symptoms of MI and treatment-seeking behaviour were collected at 24 hours after admission to the hospital. Two data collection tools were used: Patient Information Form and the Interpretation of Symptoms and Prehospital Delay Survey.

Sociodemographic characteristics and health-related information were obtained using the Patient Information Form. It is reported that sociodemographic and clinical characteristics, clinical symptoms, symptom interpretations and expectations, and cognitive and emotional variables are closely associated with prehospital delay in patients with AMI (6,13–16). Consistent with previous studies, the Patient Information Form included questions for assessment of variables associated with prehospital delay in patients with AMI.

The Interpretation of Symptoms and Prehospital Delay Survey was prepared by researchers based on previous studies to assess the patients’ symptom interpretation and factors associated with a delay between onset of AMI symptoms and hospital arrival (10,22). The questionnaire/survey was tested in a pilot study with 15 patients. Participants were asked for their comments on the clarity of each item. The feedback was assessed and small corrections were made. These 15 patients were not included in the current study sample.

The first section of the survey included questions about the presence, characteristics, onset and severity of symptoms (e.g., chest pain, cold sweating, weakness, shortness of breath, nausea, vomiting and palpitations) experienced due to AMI. Patients were asked to rate the severity of symptoms experienced during AMI between 0 and 10 (0 = none, 5 = moderate, 10 = severe). The second section comprised structured, multiple choice and semistructured questions. Prehospital delay time was recorded in minutes. Patients were classified as early (≤2 hours) or late (>2 hours) arrivers according to the time of onset of symptoms and arrival at the hospital. The third section of the survey consisted of nine structured statements, which described the interpretations of symptoms. Patients were asked to answer each statement on a 5-point Likert-type scale: strongly disagree (1), disagree (2), not sure (3), agree (4) and strongly agree (5). The total score ranged from 9 to 45. A higher score indicated that patients tended to underestimate the effects of AMI and misinterpret cardiac symptoms. The Cronbach α reliability coefficient of the third section was 0.79.

Data analysis

The data of 93 patients were analysed using SPSS version 16.0. Some descriptive statistics tools, including frequency, mean, standard deviation (SD) and percentage, were used to describe the data. The Kolmogorov–Smirnov test was used to determine the suitability of data with a normal distribution. The statistical significance was 5% (P ≤ 0.05) in all analyses. Mean scores for the Interpretation of Symptoms and Prehospital Delay Survey were compared with independent variables. The Mann–Whitney U test, a nonparametric test, was used to compare differences between two independent variables. The Kruskal–Wallis test was used to compare among > 2 independent variables. Spearman correlation analysis was used to determine relationships between variables. The early and late responders were identified with respect to certain characteristics such as sex, age group, history of heart disease and family history of heart disease. Multivariate logistic regression analysis was applied to find independent factors associated with prehospital delay. Medians and interquartile ranges (IQRs) were calculated for the delay time. The bootstrap method was used to calculate odds ratio (OR) and 95% confidence interval (CI).


Sociodemographic and clinical characteristics of participants

The mean age of the patients was 57.89 (SD 12.13) years (range: 37–82 years) and 78.5% were male (Table 1). The majority of the patients (61.3%) were diagnosed with ST segment elevation myocardial infarction (STEMI).

The first complaints of patients with AMI were reported as chest pain [8.24 (2.38)], cold sweating [5.71 (4.15)], weakness [5.20 (4.32)], shortness of breath [4.20 (4.38)], stress/panic [4.13 (4.20)], nausea/vomiting [3.04 (4.06)], palpitations [2.18 (3.43)] and indigestion [2.24 (3.63)]. Two-thirds of the patients (66.7%) felt anxious when they experienced symptoms associated with AMI. The most severe symptoms experienced by patients with MI were chest pain [8.24 (2.38)], cold sweating [5.71 (4.15)], weakness [5.20 (4.32)], feeling stressful/anxious [4.20 (4.38)], shortness of breath [4.13 (4.20)], nausea/vomiting [3.04 (4.06)], indigestion [2.24 (3.63)] and palpitation [2.18 (3.43)].

Patients’ delay in seeking treatment for AMI symptoms

Prehospital delay time ranged from 15 minutes to 10 days. The median (25th, 75th percentiles) delay time was 2 hours (1, 10.5 hours), IQR was 9.50. The information about the number of patients who were early (≤ 2 hours) or late (> 2 hours) arrivers to the hospital is presented in Table 2.

Patients reported that they reached the hospital most frequently by taxi, private car, ambulance, public transport or walking. While 52.7% of the patients presented directly to the emergency department, 47.3% were transferred from a medical centre to the current hospital for treatment. More than half of the patients (55.9%) came to the hospital with one of their relatives, 18.3% of them arrived alone, 18.3% of them arrived with their spouses and 7.5% of them arrived with friends.

The patients’ AMI symptoms most frequently began at home, and the patients frequently reported that they were with one of their family members, spouse or a friend. Nearly half (45.2%) of the patients reported that they were directed to the hospital by the person who was with them. When the patients first noticed their cardiac symptoms, they waited for the pain to disappear (48.4%), tried to calm down (39.8%), began to think about going to the hospital (35.5%), tried to convince themselves that they were not having a critical health problem (34.4%), used medication (34.4%), went to the hospital (33.3%), tried to relax (31.2%), tried not to think about their complaints (14%), or prayed for symptoms to disappear (15.1%). Only a small group of patients called the ambulance (emergency service) (3.2%) or went to the doctor (1.1%) as a first action when they noticed their AMI symptoms.

Symptom interpretation and predictors that may contribute to prehospital delay

Patients often associated their AMI-related complaints with reasons other than heart disease. Most of the patients (81.7%) stated that awareness or understanding of which symptoms are indicative of heart problems would significantly increase the rate of admission to the hospital.

Most of the patients (33.3%) stated that they did not consider their complaints to be serious and expected to recover (Table 3). Most patients (43%) reported that their complaints were ongoing and they did not immediately cease. The majority (45.2%) of the patients reported that they did not attribute symptoms to cardiac causes. From the Interpretation of Symptoms and Prehospital Delay Survey, the response “I could not understand that the complaints were related to the heart” had the highest score [3.62 (1.48)], and “I thought that the complaints were due to my age” had the lowest score [2.75 (1.29)]. The mean score was 28.32 (7.69) (range: 9–45).

We found significant differences between scores with respect to type of AMI and a history of heart disease (P < 0.05) (Table 4). The scores of the patients diagnosed with non-ST segment elevation myocardial infarction (NSTEMI) [30.89 (6.02)] were significantly higher than the scores of patients diagnosed with STEMI [26.70 (8.23)] (Zmwu = −2.134, P = 0.033). The scores of the patients with no history of heart disease [29.29 (7.50)] were significantly higher than the scores of patients with a history of heart disease [25.39 (7.69)] (Zmwu = −1.968, P = 0.049). There were no significant differences in the Interpretation of Symptoms and Prehospital Delay Survey with regard to sex or education level (P > 0.05). In addition, there were no significant differences with respect to the regularity of health control, history of bypass surgery, a history of chronic disease, or family history of heart disease (P > 0.05). There were also no significant differences in the Interpretation of Symptoms and Prehospital Delay Survey scores with regard to variables such as a mode of transportation to the hospital, person (companion/attendant/escort) who came to the hospital with the patient, presence of anxiety when complaints began and knowledge about the aetiology of these complaints (P > 0.05).

Older patients (aged ≥ 60 years) obtained higher survey scores than younger patients (P < 0.005) (Table 4). There was a positive and low-level significant correlation between age of the patients and scores of Interpretation of Symptoms and Prehospital Delay Survey (rs = 0.25, P < 0.05).

In a multivariate logistic regression analysis, the type of AMI (OR: 5.18, 95% CI: 1.69–15.91, P = 0.004) was independently associated with a long prehospital delay time, indicating that patients with STEMI would seek early and immediate medical care (Table 5).


The success of treatment and better outcomes in patients with AMI depends on early initiation of interventions. The duration between the onset of symptoms and initiation of treatment is long for most patients (23–25). In the current study, the prehospital delay time ranged from 15 minutes to 10 days, and the median prehospital delay was 2 hours.

Patients cannot appraise their symptoms as serious or originating from the heart and thus arrival to hospital is delayed (11,26). One study reported that the patients with AMI (41%) did not interpret their symptoms as being of cardiac origin (27). Other studies have reported that delays were longer in patients with AMI who did not appraise their symptoms as being serious or originating from the heart (7,10,12,28). Mussi et al. found that those who did not recognize the symptoms of AMI and did not manage pain effectively took longer before deciding to seek treatment and present to a hospital (7). Recognizing that symptoms are coming from the heart is an important factor leading patients to seek early hospital treatment (11,12).

Patients with AMI often tend to rest, wait for their symptoms to cease and pray for recovery at the onset of symptoms (10,11,24). Consistent with these studies, we found that patients waited for recovery and tried to calm themselves down when they first noticed their complaints. These findings show the need for public education that is aimed at increasing awareness of symptoms of AMI and the importance of shortening delay in seeking assistance.

Lack of knowledge about specialized facilities for primary cardiac interventions for AMI, and transportation to the hospital, are the leading causes of delays. Nearly half of the current sample (47.3%) was transferred from another medical centre to the university hospital for emergency treatment. Transfer from one medical centre to another causes delays for early treatment of AMI. This indicates the importance of increasing public awareness about specialized hospitals for urgent treatment of AMI. Increasing the number of specialized centres for emergency intervention, increasing awareness among at-risk groups about specialized cardiac units, and informing healthcare professionals about the urgent healthcare chain will help avoid delays.

The support of family and friends is crucial in emergency cases. In the current study, cardiac complaints began at home for two-thirds of the patients. One-third of the patients had one of their family members with them during the onset of symptoms, and approximately half of the patients were directed to the hospital by the person who was with them when they experienced complaints.

The current study was limited by the small sample of 93 patients who were hospitalized. The data on delays were collected using a survey prepared by the researcher, therefore, data collection was subjective.

In conclusion, understanding the associations of symptom interpretation and early symptoms with prehospital delay will help clinicians to develop strategies to increase public awareness of the importance of acting timely with suspected AMI. Our results reveal that increasing awareness of AMI symptoms, support for interpretation of AMI-related symptoms, and timely medical and social support will shorten delays. A further study should be conducted to investigate the influence of traffic problems in Istanbul on delay in reaching the hospital.

Funding: None.

Competing interests: .None declared.


  1. American College of Emergency Physicians; Society for Cardiovascular Angiography and Interventions, O'Gara PT, Kushner FG, Ascheim DD, Casey DE Jr, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2013 Jan 29;61(4):e78–140. PMID:23256914
  2. Davis LL, Mishel M, Moser DK, Esposito N, Lynn MR, Schwartz TA. Thoughts and behaviors of women with symptoms of acute coronary syndrome. Heart Lung. 2013 Nov-Dec;42(6):428–35. PMID:24011604
  3. Neubeck L, Maiorana A. Time to get help? Acute myocardial infarction and delay in calling an ambulance. Heart Lung Circ. 2015 Jan;24(1):1–3. PMID:25201029
  4. Nielsen PH, Terkelsen CJ, Nielsen TT, Thuesen L, Krusell LR, Thayssen P, et al. System delay and timing of intervention in acute myocardial infarction (from the Danish Acute Myocardial Infarction-2 [DANAMI-2] trial). Am J Cardiol. 2011 Sep 15;108(6):776–81. PMID:21757183
  5. Preti A, Sancassiani F, Cadoni F, Carta MG. Alexithymia affects pre-hospital delay of patients with acute myocardial infarction: meta-analysis of existing studies. Clin Pract Epidemol Ment Health. 2013 Apr 19;9:69–73. PMID:23878612
  6. Peng YG, Feng JJ, Guo LF, Li N, Liu WH, Li GJ, et al. Factors associated with prehospital delay in patients with ST-segment elevation acute myocardial infarction in China. Am J Emerg Med. 2014 Apr;32(4):349–55. PMID:24512889
  7. Mussi FC, Mendes AS, Queiroz TL, Costa AL, Pereira Á, Caramelli B. Pre-hospital delay in acute myocardial infarction: judgement of symptoms and resistance to pain. Rev Assoc Med Bras. 2014 Jan-Feb;60(1):63–9. PMID:24918855
  8. Ahmadi A, Soori H, Mehrabi Y, Etemad K, Samavat T, Khaledifar A. Incidence of acute myocardial infarction in Islamic Republic of Iran: a study using national registry data in 2012. East Mediterr Health J. 2015 Feb 25;21(1):5–12. PMID:25907187
  9. Norgaz T, Hobikoğlu G, Aksu H, Esen A, Gül M, Özer HO, et al. ST yükselmeli akut miyokard infarktüsünde hastane öncesi gecikme süresi ile klinik, demografik ve sosyoekonomik etkenlerin ilişkisi: hasta eğitiminin önemi [The relationship between prehospital delays of patients with ST-elevation acute myocardial infarction and clinical, demographic, and socioeconomic factors: importance of patient education]. Turk Kardiyol Dern Ars. 2005;33(7):392–7 (in Turkish)
  10. Dracup K, Moser KD. Beyond sociodemographics: factors influencing the decision to seek treatment for symptoms of acute myocardial infarction. Heart Lung. 1997 Jul-Aug;26(4):253–62. PMID:9257135
  11. Lesneski L, Morton P. Delay in seeking treatment for acute myocardial infarction: why? J Emerg Nurs. 2003 Apr;26(2):125–9. PMID:10748384
  12. Taghaddosi M, Dianati M, Fath Gharib Bidgoli J, Bahonaran J. Delay and its related factors in seeking treatment in patients with acute myocardial infarction. ARYA Atheroscler. 2010 Spring;6(1):35–41. PMID:22577411
  13. Abed MA, Abu Ali RM, Abu Ras MM, Hamdallah FO, Khalil AA, Moser DK. Symptoms of acute myocardial infarction: A correlational study of the discrepancy between patients’ expectations and experiences. Int J Nurs Stud. 2015 Oct;52(10):1591–9. PMID:26184390
  14. Khraim FM, Scherer YK, Dorn JM, Carey MG. Predictors of decision delay to seeking health care among Jordanians with acute myocardial infarction. J Nurs Scholarsh. 2009;41(3):260–7. PMID:19723274
  15. Ghazawy ER, Seedhom AE, Mahfouz EM. Predictors of delay in seeking health care among myocardial infarction patients. Minia District, Egypt. Adv Prev Med. 2015;Article ID:342361, 6 pages (
  16. Pitsavos C, Kourlaba G, Panagiotakos DB, Stefanadis C; GREECS Study Investigators. Factors associated with delay in seeking health care for hospitalized patients with Acute Coronary Syndromes: The GREECS Study. Hellenic J Cardiol. 2006 Nov-Dec;47(6):329–36. PMID:17243504
  17. Granot M, Dagula P, Darawshac W, Aronson D. Pain modulation efficiency delays seeking medical help in patients with acute myocardial infarction. Pain. 2015 Jan;156(1):192–8. PMID:25599315
  18. Heo JY, Hong KJ, Shin SD, Song KJ, Ro YS. Association of educational level with delay of prehospital care before reperfusion in STEMI. Am J Emerg Med. 2015 Dec;33(12):1760–9. PMID:26349779
  19. Song L, Yan HB, Hu DY, Yang JG, Sun YH. Pre-hospital care seeking in patients with acute myocardial infarction and subsequent quality of care in Beijing. Chin Med J (Engl). 2010 Mar 20;123(6):664–9. PMID:20368083
  20. Hong CC, Sultana P, Wong AS, Chan KP, Pek PP, Ong ME. Prehospital delay in patients presenting with acute ST-elevation myocardial infarction. Eur J Emerg Med. 2011 Oct;18(5):268–71. PMID:21317785
  21. Fukuoka Y, Dracupa K, Rankin SH, Froelicher ES, Kobayashi F, Hirayama H, et al. Prehospital delay and independent/interdependent construal of self among Japanese patients with acute myocardial infarction. Soc Sci Med. 2005 May;60(9):2025–34. PMID:15743651
  22. Dracup K, Moser DK, McKinley S, Ball C, Yamasaki K, Kim CJ, et al. An International perspective on the time to treatment for acute myocardial infarction. J Nurs Scholarsh. 2003;35(4):317–23. PMID:14735673
  23. Saberi F, Adib-Hajbaghery M. Zohrehea J. Predictors of prehospital delay in patients with acute myocardial infarction in Kashan city. Nurs Midwifery Stud. 2014 Dec;3(4):e24238. PMID:25741517
  24. Yardımcı T. İlk kez akut miyokard infarktüsü geçiren bireylerin tıbbi yardım isteme konusunda nasıl karar verdiklerinin incelenmesi [Evaluation of decision process of individuals while seeking medical help during first acute myocardial infarction]. [thesis] Dokuz Eylül Üniversitesi Sağlık Bilimleri Enstitüsü. Yüksek Lisans Tezi, İzmir; 2010 (in Turkish)
  25. Gao Y, Zhang HJ. The Effect of symptoms on prehospital delay time in patients with acute myocardial infarction. J Int Med Res. 2013 Oct;41(5):1724–31. PMID:23926196
  26. Horne R, James D, Petrie K, Weinman J, Vincent R. Patients’ interpretation of symptoms as a cause of delay in reaching hospital during acute myocardial infarction. Heart. 2000 Apr;83(4):388–93. PMID: 10722534
  27. Mussi FC, Gibaut Mde A, Damasceno CA, Mendes AS, Guimarães AC, Santos CA. Sociodemographic and clinical factors associated with the decision time for seeking care in acute myocardial infarction. Rev Lat Am Enfermagem. 2013 Nov-Dec;21(6):1248–57. PMID:24271318
  28. Damasceno CA, de Queiroz TL, Santos CA, Mussi FC. [Factors associated with the decision to seek health care in myocardial infarction: gender differences]. Rev Esc Enferm USP. 2012 Dec;46(6):1362–70 (in Portuguese). PMID:23380779